1. Field of the Invention
This invention relates to a combustor for burning fuel and, more specifically, to a combustor, such as a gas turbine combustor, for burning fuel and compressed air, and sensing the level of a contaminant, such as sodium, within the combustion flame. The invention also relates to a method for burning fuel and sensing the level of a contaminant within the combustion flame.
2. Background Information
In a gas turbine, fuel is burned with compressed air, produced by a compressor. The combustion reaction takes place in one or more combustors. An example of such a combustor is disclosed in U.S. Pat. No. 5,361,586, which is incorporated by reference herein.
Substantial costs may arise due to corrosion of hot-section components of the gas turbine, including the combustors. Sodium, for example, is an extremely corrosive contaminant, even in small concentrations, to any hot-section component in the gas turbine.
Currently, fuel contaminants are typically identified by random, periodic fuel sampling. This requires both a technician, who is skilled in laboratory analysis, and a relatively expensive atomic emission spectrometer. However, problems may result due to the periodic nature of the sampling. For example, during periods when no fuel is sampled, it is possible for salt water (i.e., containing sodium) to contaminate the fuel, enter into the combustor, and initiate hot corrosion thereof.
It is, therefore, desirable to provide a combustor with a non-obtrusive, economical, real-time, contaminant sensing function.